Exploration group Regency Mines is set to acquire a 5% stake in the Horse Hill Development (HHDL) near Gatwick Airport.The group has signed an agreement which will see it pay £0.3m to HHDL, the newly-incorporated special purpose vehicle which rights to buy a 65% in the Petroleum Exploration and Development Licence 137 (PEDL 137).Regency's investment follows a decision by Alba Minerals, in which it currently holds a 14.87% direct stake, to participate in the HHDL project.Other investors in HHDL include Angus Energy, Solo Oil , Doriemus , Stellar Resources and UK Oil & Gas Investments.Regency Chairman Andrew Bell said: "The opportunity to invest with Alba, Angus Energy, and the other investors in this exciting UK oil and gas project follows extensive due diligence and analysis. "By co-investing with Alba, Regency supports Alba in its strategic re-launch into the oil and gas space, which Regency has been assisting." As of 10:22 the share price had risen 3.92% to 0.26p.WS